Immigrationboards.com

https://www.gov.uk/indefinite-leave-to- ... it%20later.
Below info is from GOV.UK website

Apply online
You must apply online.

The earliest you can apply is 28 days before you’ve lived in the UK long enough. Your application may be refused if you apply earlier.

Do not wait until your current visa expires. If your visa expires before you can apply for indefinite leave to remain, you’ll need to renew it first.

Once you’ve started your application, you can save your form and complete it later.

Hi Zimba,
I am in very similar situation.
I got ILR. My dependant family's skilled worker dependant visa expires on 14th Jan 2026.Their 28day ILR application window starts on 2nd Feb 2026.
If I directly apply for their ILR on 13th Jan, will the application be refused (though I do Biometric after 2 Feb). In short the date of ILR application is date of online submission or date of biometric?

Secondly, If I apply for their Extension before 14Jan, and delay biometric beyond 2nd Feb. Should I make new ILR application or Vary my extension application? Can I get refund on 3year extension IHS & processing fees?
Thank you

The advice on this issue has been repeated literally hundreds of times on this forum without a single case of failure. You need to understand how the immigration rules work. Gov.UK is NOT a place to seek clarification on the immigration rules and procedures !!

Read this post --> All you need to know about applying early, the application date, 28-day concession and more

Only seek advice after you carefully read and understood the advice in my post above !!!